Antimicrobial resistance and resistance genes in Escherichia coli isolated from retail meat purchased in Alberta, Canada

This study analyzed antimicrobial resistance (AMR) and resistance genes in generic Escherichia coli isolated from retail meat samples purchased (2007-2008) in Alberta, Canada, and determined potential associations between resistance phenotypes and resistance genes with relation to the meat types. A total of 422 E. coli isolates from retail chicken, turkey, beef, and pork meats were tested for antimicrobial susceptibility. Multiplex PCRs were used to detect major resistance genes for tetracyclines [tet(A), tet(B), tet(C)], sulfonamides (sul1, sul2, sul3), aminoglycosides (strA/B, aadA, aadB, aac(3)IV, aphA1, aphA2), and β-lactamase (bla(CMY-2), bla(TEM), bla(SHV), bla(PSE-1)). Resistance to ciprofloxacin was not found in any isolate. Overall resistances to clinically important antimicrobials amoxicillin-clavulanic acid (16.8% of isolates) and ceftriaxone (12.6% isolates) were observed. These resistances were observed more frequently (p<0.0001) in chicken-derived E. coli than those from the other meat types. Resistance to multiple antimicrobials (≥ 5) was found in more chicken derived E. coli (32%) than E. coli from other meat types. The β-lactamase genes of clinical importance, including bla(CMY-2) and bla(TEM), were found in about 18% of poultry-derived E. coli and in only 5% of ground beef. The bla(CMY-2) gene was more likely to be found in E. coli from chicken than turkey, beef, or pork meats. The tet(A) gene was associated with bla(CMY-2), whereas bla(CMY-2) and bla(TEM) genes were associated with strA/B genes. Resistance genes for tetracycline, sulfonamides, and aminoglycosides were associated with the phenotypic expression of resistance to unrelated classes of antimicrobials. These data suggest the prevalence of AMR and select resistance genes were higher in poultry-derived E. coli. The multiple associations found between AMR phenotypes and resistance genes suggest a complex nature of resistance in E. coli from retail meat, and hence the use of a single antimicrobial could result in the selection of resistant E. coli not only to the drug being used but to other unrelated classes of antimicrobials as well.     

产ESBLs肺炎克雷伯菌β-内酰胺酶基因检测

目的 了解产超广谱β-内酰胺酶(ESBLs)肺炎克雷伯菌临床分离株中β-内酰胺酶(bla)基因流行状况.方法 采用美国临床实验室标准化研究所(CLSI)推荐的的表型筛选与确证试验检测ESBLs,应用PCR扩增产ESBLs菌株bla(TEM)、bla(SHV)、bla(CTX-M)基因,并对PCR阳性产物进行克隆后测序确定其基因亚型.结果 46株产ESBLs肺炎克雷伯菌中,基因检出率分别为bla(TEM)11株,占23.9%;bla(SHV)13株,占28.3%;bla(CTX-M)43株,占93.5%;携带1种bla基因菌株21株,占45.7%;携带2种20株,占43.5%;携带3种3株,占6.5%;全部菌株bla(TEM)基因测序结果均为TEM-1亚型,bla(SHV)基因为SHV-11、12、28亚型;部分菌株bla(CTX-M)基因测序结果为CTX-M-15、24、38亚型.结论 产ESBLs肺炎克雷伯菌中ESBLs基因型以CTX-M型为主,其次为SHV型,部分菌株同时携带广谱β-内酰胺酶基因TEM-1或SHV-11;监测产ESBLs细菌β-内酰胺酶基因流行状况,有助于指导临床合理应用抗生素.     

Emergence of metallo-β-lactamase IMP-14 and VIM-2 in Pseudomonas aeruginosa clinical isolates from a tertiary-level hospital in Thailand

Seventy-five clinical isolates of Pseudomonas aeruginosa collected in a tertiary teaching hospital in Thailand were investigated for susceptibility to antimicrobials including imipenem. Metallo-β-lactamase (MBL) enzymes were detected by E-test MBL assay and PCR; class 1 integron genes were also detected by PCR. Strains positive for bla(IMP) and bla(VIM) genes were further characterized by DNA sequencing and examined for clonality by pulsed-field gel electrophoresis. High rates of resistance to anti-pseudomonal agents were found. MBL enzymes were found in 13 (17·3%) strains and 24 (32%) carried class 1 integron genes. Twelve of the latter strains harboured the bla(IMP-14) gene and one strain the bla(VIM-2) gene. All of the IMP-14 strains were identical or closely related suggesting clonal dissemination of these genes.     

Phylogenetic analysis of carbapenem-resistant Acinetobacter baumannii isolated from different sources using Multilocus Sequence Typing Scheme

The emergence and worldwide distribution of carbapenem-resistant Acinetobacter baumannii strains has become a major public health threat. The objective of this study was to investigate the clonal relatedness of A. baumannii isolates collected from clinical and extra-hospital environments in Mthatha, South Africa. Forty carbapenem-resistant isolates comprising of clinical (20) and extra-hospital (20) were identified and tested for antimicrobial susceptibility. Detection of carbapenemase encoding genes was performed by Real-time PCR. The clonal relationship of clinical isolates relative to extra-hospital isolates was determined via multilocus sequence typing (MLST). All isolates (clinical and extra-hospital) were resistant to most common antibiotics including carbapenems (imipenem; MIC ≥32 μg/mL and meropenem; MIC ≥32 μg/mL) with the only exception being amikacin (with 3 isolates susceptible), tigecycline (14 isolates susceptible) and colistin (all isolates susceptible). The bla OXA-23-like and the intrinsic bla OXA-51 -like genes were detected in all the isolates tested. The bla OXA-58-like and bla IMP-type genes were detected in 2 clinical isolates whilst the bla OXA-24-like, bla VIM-type, bla NDM-1, bla SIM, and bla AmpC were not detected. The bla OXA-24-like, bla OXA-58-like, bla IMP-type, bla VIM-type, bla NDM-1, bla SIM, and bla AmpC were negative in the extra-hospital isolates. Co-occurrence of bla OXA-23 -like, bla OXA-58-like and bla IMP-type was observed in 2 clinical isolates. The MLST performed on 33 isolates identified 5 existing sequence types (ST) (ST1, ST2, ST25, ST85 and ST215) in clinical isolates and 2 existing STs (ST1 and ST2) in extra-hospital isolates. The most dominant ST was ST2 accounting for 68.8% of the clinical isolates and 82.4% of the extra-hospital isolates. The study demonstrated high prevalence and potential clonal spread of globally-disseminated clonal complex 2 carrying bla OXA-23-like within our local settings. However, ST25 might be an emerging lineage carrying the bla OXA-23-like . Continuous monitoring is important in limiting the spread of these strains in other healthcare settings and the community.     

A survey of β-lactamase and 16S rRNA methylase genes among fluoroquinolone-resistant Escherichia coli isolates and their horizontal transmission in Shandong, China

The prevalence of β-lactamase, 16S rRNA methylase genes, and plasmid-mediated fluoroquinolone-resistance (PMQR) determinants (qnrC and qnrD) was determined by polymerase chain reaction in fluoroquinolone-resistant Escherichia coli isolated from a chicken farm, a pig farm, and a hospital in Shandong, China in 2007. The bla(TEM) and bla(CTX-M) were the most prevalent β-lactamase genes in isolates from chickens (88.4%, 175/198 and 81.3%, 161/198) and hospitalized patients (87.8%, 122/139 and 69.1%, 96/139). The bla(TEM) was the most prevalent β-lactamase gene observed in isolates from pigs (98.5%, 135/137). The gene bla(CMY-2) was also predominant among isolates from chickens (20.2%, 40/198). The bla(LAP-1) gene was first detected in one strain from chickens and humans (pig farm workers) in China. Only one strain from hospitalized patients was found to possess bla(SHV). The rmtB was the most prevalent 16S rRNA methylase gene detected in isolates from chickens (19.7%, 39/198) and hospitalized patients (15.8%, 22/139). To our knowledge, this is the first report of the detection of the qnrD gene in E. coli from chickens and pigs in China. The qnrC and bla(KPC) genes were not detected in any of the isolates. Results of southern hybridization revealed that PMQR determinants, β-lactamases, and 16S rRNA methylase genes were located on the same plasmid in E. coli strains derived from patients. Also, PMQR determinants and β-lactamase genes were localized on the same plasmid in an E. coli strain of animal origin. Results of conjugation experiments revealed that all of these plasmid-based resistance genes can be transferred by conjugation through horizontal transmission.     

Genetic analysis of antibiotic-resistance determinants in multidrug-resistant Shigella strains isolated from Chilean children

A total of 162 clinical isolates of Shigella collected from children in a semi-rural community of Chile were examined for the presence of genetic determinants of resistance to ampicillin, chloramphenicol, tetracycline, and trimethoprim. Ampicillin resistance was most frequently associated with the presence of bla(OXA) in S. flexneri and with bla(TEM) in S. sonnei. The bla(OXA) gene but not bla(TEM) was located in class 1 integrons. The dhfrIa gene encoding for resistance to trimethoprim was associated to class 2 integrons and detected exclusively in S. flexneri, whereas dhfrIIIc was found in all S. sonnei strains and in 10% of the S. flexneri isolates. Cat, coding for choramphenicol resistance, and bla(OXA) genes were located in the chromosome in all cases, whereas tetA gene, coding for tetracycline resistance, and bla(TEM), dhfrIa and dhfrIIIc genes were found either in the chromosome or in conjugative plasmids. Our results show a heterogenous distribution of antibiotic-resistance determinants between S. flexneri and S. sonnei.     

肿瘤医院产超广谱β-内酰胺酶大肠埃希菌分布及基因型研究

目的了解医院感染的产超广谱β-内酰胺酶(ESBLs)大肠埃希菌医院感染的临床分布及其基因型特征。方法用表型确证试验确定临床标本中产ESBLs大肠埃希菌80株,应用PCR方法分别扩增产酶菌株的TEM、SHV和CTX-M 3种β-内酰胺酶基因,并对PCR扩增结果及ESBLs株临床分布进行分析。结果 PCR扩增结果显示,CTX-M、TEM和SHV基因的阳性率分别为79.5%、12.8%和18.2%;42.3%的菌株同时携带多个基因;产ESBLs大肠埃希菌广泛分布于各个临床科室,其中普外科占32.5%,肝胆外科和重症监护病房均占23.8%;标本分布较为集中,41.3%来自腹腔引流液,23.8%来自呼吸道标本,12.5%来自尿液。结论医院感染中,产ESBLs大肠埃希菌的主要基因型是CTX-M,腹腔引流液、呼吸道标本、尿液是其主要标本来源,CTX-M型产ESBLs菌分布广泛,应特别加强对它的监测,预防医院感染暴发流行。     

Endemic carbapenem-resistant Pseudomonas aeruginosa with acquired metallo-beta-lactamase determinants in European hospital

Acquired metallo-beta-lactamases (MBLs) can confer broad-spectrum beta-lactam resistance (including carbapenems) not reversible by conventional beta-lactamase inhibitors and are emerging resistance determinants of remarkable clinical importance. In 2001, multidrug-resistant Pseudomonas aeruginosa carrying bla(VIM) MBL genes were found to be widespread (approximately 20% of all P. aeruginosa isolates and 70% of the carbapenem-resistant isolates) at Trieste University Hospital. Clonal diversity and heterogeneity of resistance determinants (either bla(VIM-1)-like or bla(VIM-2)-like) were detected among MBL producers. This evidence is the first that acquired MBLs can rapidly emerge and establish a condition of endemicity in certain epidemiologic settings.     

Characterization of extended-spectrum cephalosporin-resistant Salmonella enterica serovar Heidelberg isolated from food animals, retail meat, and humans in the United States 2009

Salmonella enterica is one of the most common causes of foodborne illness in the United States. Although salmonellosis is usually self-limiting, severe infections typically require antimicrobial treatment, and ceftriaxone, an extended-spectrum cephalosporin (ESC), is commonly used in both adults and children. Surveillance conducted by the National Antimicrobial Resistance Monitoring System (NARMS) has shown a recent increase in ESC resistance among Salmonella Heidelberg isolated from food animals at slaughter, retail meat, and humans. ESC resistance among Salmonella in the United States is usually mediated by a plasmid-encoded bla(CMY) β-lactamase. In 2009, we identified 47 ESC-resistant bla(CMY)-positive Heidelberg isolates from humans (n=18), food animals at slaughter (n=16), and retail meats (n=13) associated with a spike in the prevalence of this serovar. Almost 90% (26/29) of the animal and meat isolates were isolated from chicken carcasses or retail chicken meat. We screened NARMS isolates for the presence of bla(CMY), determined whether the gene was plasmid-encoded, examined pulsed-field gel electrophoresis patterns to assess the genetic diversities of the isolates, and categorized the bla(CMY) plasmids by plasmid incompatibility groups and plasmid multi-locus sequence typing (pMLST). All 47 bla(CMY) genes were found to be plasmid encoded. Incompatibility/replicon typing demonstrated that 41 were IncI1 plasmids, 40 of which only conferred bla(CMY)-associated resistance. Six were IncA/C plasmids that carried additional resistance genes. pMLST of the IncI1-bla(CMY) plasmids showed that 27 (65.8%) were sequence type (ST) 12, the most common ST among bla(CMY)-IncI1 plasmids from Heidelberg isolated from humans. Ten plasmids had a new ST profile, ST66, a type very similar to ST12. This work showed that the 2009 increase in ESC resistance among Salmonella Heidelberg was caused mainly by the dissemination of bla(CMY) on IncI1 and IncA/C plasmids in a variety of genetic backgrounds, and is likely not the result of clonal expansion.     

VIM-1 metallo-beta-lactamase in Acinetobacter baumannii

In 2004 and 2005, 5 metallo-beta-lactamase (MBL)-positive Acinetobacter baumannii isolates were found in 2 Greek hospitals. Isolates were unrelated and carried blaVIM-1 in a class 1 integron; bla(OXA-51-) and bla(OXA-58-like) carbapenemase genes were also detected. VIM-1 MBL in Acinetobacter spp. causes concern, given the increasing resistance of this species.     

Characterization of bla(CMY)-encoding plasmids among Salmonella isolated in the United States in 2007

Salmonella enterica is one of the most common bacterial causes of foodborne illness, and nontyphoidal Salmonella is estimated to cause ～1.2 million illnesses in the United States each year. Plasmids are mobile genetic elements that play a critical role in the dissemination of antimicrobial resistance determinants. AmpC-type CMY β-lactamases (bla(CMY)) confer resistance to extended-spectrum cephalosporins and β-lactam/β-lactamase inhibitor combinations and are commonly plasmid-encoded. A variety of plasmids have been shown to encode CMY β-lactamases and certain plasmids may be associated with particular Salmonella serotypes or environmental sources. In this study, we characterized bla(CMY) β-lactamase-encoding plasmids among Salmonella isolates. Isolates of Salmonella from specimens collected from humans in 2007 were submitted to the Centers for Disease Control and Prevention National Antimicrobial Resistance Monitoring System laboratory for susceptibility testing. Three percent (65/2161) of Salmonella isolates displayed resistance to ceftriaxone (minimum inhibitory concentration [MIC] ≥4?mg/L) and amoxicillin/clavulanic acid (MIC ≥32?mg/L), a combination associated with the presence of a bla(CMY) mechanism of resistance. Sixty-four (98.5%) isolates were polymerase chain reaction-positive for bla(CMY) genes. Transformation and conjugation studies showed that 95% (61/64) of the bla(CMY) genes were plasmid-encoded. Most of the bla(CMY)-positive isolates were serotype Typhimurium, Newport, Heidelberg, and Agona. Forty-three plasmids were replicon type IncA/C, 15 IncI1, 2 contained multiple replicon loci, and 1 was untypeable. IncI1 plasmids conferred only the bla(CMY)-associated resistance phenotype, whereas IncA/C plasmids conferred additional multi-drug resistance (MDR) phenotypes to drugs such as chloramphenicol, sulfisoxazole, and tetracycline. Most of the IncI1 plasmids (12/15) were sequence type 12 by plasmid multi-locus sequence typing. CMY β-lactamase-encoding plasmids among human isolates of Salmonella in the United States tended to be large MDR IncA/C plasmids or single resistance determinant IncI1 plasmids. In general, IncI1 plasmids were identified among serotypes commonly associated with poultry, whereas IncA/C plasmids were more likely to be identified among cattle/beef-associated serotypes.     

大肠埃希菌对β-内酰胺类药物耐药特征及分子流行病学研究

目的 调查大肠埃希菌尿液分离株中β-内酰胺酶基因、AmpC酶基因和膜孔蛋白ompC基因的存在和变异情况.方法 对宁波市第一医院2008年10月至2009年3月患者尿液样本中分离的大肠埃希菌(28株)采用PCR及序列分析的方法,分析15种β-内酰胺酶基因、6种AmpC酶基因和膜孔蛋白ompC基因.结果 28株大肠埃希菌仅...     

Gilthead seabream (Sparus aurata) as carriers of SHV-12 and TEM-52 extended-spectrum beta-lactamases-containing Escherichia coli isolates

In recent years, bacterial resistance to beta-lactam antibiotics has risen dramatically in Escherichia coli isolated from animals that could pass through the food chain to humans. One hundred eighteen fecal samples of Sparus aurata were tested for extended-spectrum beta-lactamase (ESBL)-containing E. coli recovery. Susceptibility to 16 antimicrobial agents was performed by disk diffusion. ESBL-phenotypic detection was carried out by double-disk test, and the presence of genes encoding TEM, OXA, SHV, and CTX-M type beta-lactamases was studied by polymerase chain reaction and sequencing. The detection of other antimicrobial resistance mechanisms and phylogenetic groups was also performed in recovered isolates as well as their clonal diversity by pulsed-field gel electrophoresis. Five of the 118 fecal samples harbored ESBL-positive E. coli isolates (4.2%), and one isolate per sample was completely characterized. These five ESBL-positive E. coli isolates contained the bla(TEM-52) or bla(SHV-12) genes, as well as a variety of other resistance genes (cmlA, tetA, aadA, sul1, sul2, and sul3). Four isolates harbored class 1 integrons with the following gene cassettes in their variable region: dfrA1 + aadA1 (one isolate) and sat + psp + aadA2 (three isolates). Four unrelated pulsed-field gel electrophoresis patterns were identified among the five ESBL-positive isolates, and they were ascribed to phylogroups A and B1. The intestinal tract of S. aurata might constitute a reservoir of ESBL-producing E. coli isolates.     

Salmonella enterica and Escherichia coli harboring blaCMY in retail beef and pork products

We estimated the proportion of retail beef and pork products containing bla(CMY)-mediated third-generation cephalosporin resistance in commensal Escherichia coli and Salmonella enterica. Samples were obtained from 50 grocery stores located in two U.S. states. From each store, 20 fresh meat products were purchased, including 7 packages of ground beef, 3 packages of beef steak, 6 packages of pork chops, and 4 packages of pork ribs. The resulting 1000 packages of fresh meat product were individually screened for the presence of E. coli or Salmonella harboring bla(CMY). Over 8% of all retail meat packages contained E. coli with bla(CMY), whereas 4% contained Salmonella and only 0.5% contained Salmonella with bla(CMY). Retail pork products more frequently yielded E. coli with bla(CMY) than did beef products (12.2% vs. 4.0%; p?=?0.06). Salmonella were also recovered more frequently from pork than beef (5.8% vs. 2.4%; p?相似文献   

CTX-M-producing non-Typhi Salmonella spp. isolated from humans, United States

CTX-M-type beta-lactamases are increasing among US Enterobacteriaceae isolates. Of 2,165 non-Typhi Salmonella isolates submitted in 2007 to the National Antimicrobial Resistance Monitoring System, 100 (4.6%) displayed elevated MICs (≥2 mg/L) of ceftriaxone or ceftiofur. Three isolates (serotypes Typhimurium, Concord, and I 4,5,12:i:-) contained bla(CTX-M-5), bla(CTX-M-15), and bla(CTX-M-55/57), respectively.     

Human Salmonella and concurrent decreased susceptibility to quinolones and extended-spectrum cephalosporins

The National Antimicrobial Resistance Monitoring System monitors susceptibility among Enterobacteriaceae in humans in the United States. We studied isolates exhibiting decreased susceptibility to quinolones (nalidixic acid MIC >32 microg/mL or ciprofloxacin MIC > or =0.12 microg/mL) and extended-spectrum cephalosporins (ceftiofur or ceftriaxone MIC > or =2 microg/mL) during 1996-2004. Of non-Typhi Salmonella, 0.19% (27/14,043) met these criteria: 11 Senftenberg; 6 Typhimurium; 3 Newport; 2 Enteridis; and 1 each Agona, Haifa, Mbandaka, Saintpaul, and Uganda. Twenty-six isolates had gyrA mutations (11 at codon 83 only, 3 at codon 87 only, 12 at both). All Senftenberg isolates had parC mutations (S801 and T57S); 6 others had the T57S mutation. The Mbandaka isolate contained qnrB2. Eight isolates contained bla(CMY-2); 1 Senftenberg contained bla(CMY-23). One Senftenberg and 1 Typhimurium isolate contained bla(SHV-12); the Mbandaka isolate contained bla(SHV-30). Nine Senftenberg isolates contained bla(OXA-1) contained bla(OXA-9). Further studies should address patient outcomes, risk factors, and resistance dissemination prevention strategies.     

bla(NDM-1)-positive Klebsiella pneumoniae from Environment, Vietnam

TO THE EDITOR: The bla(NDM-1) gene, which produces the New Delhi metallo-β-lactamase (NDM-1) enzyme, confers resistance to the carbapenem class of antimicrobial drugs and can be transferred among different types of bacteria. NDM-1 was identified in 2008 in Sweden from a patient from India who had been hospitalized in New Delhi (1). Since that report, bla(NDM-1)-positive bacteria have been identified from patients in several countries; most of these patients had a direct link with the Indian subcontinent (2). The spread of bla(NDM-1) among bacterial pathogens is of concern not only because of resistance to carbapenems but also because such pathogens typically are resistant to multiple antimicrobial drug classes, which leaves few treatment choices available (3-5). In 2011, spread of bla(NDM-1)-positive bacteria in an environmental setting in New Delhi was reported (6).     

Molecular characterization of Salmonella enterica serotype Enteritidis isolates from humans by antimicrobial resistance, virulence genes, and pulsed-field gel electrophoresis

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major serovar associated with human salmonellosis. A total of 425 clinical S. Enteritidis isolates of human origin were collected between June 2009 and September 2010 from North Carolina. The isolates were further characterized for antimicrobial susceptibility, antimicrobial resistance coding determinants, virulence genes, and fingerprint profiles to determine whether they were similar or different to the S. Enteritidis strain responsible for the human outbreak due to consumption of contaminated eggs. Ten different antimicrobial resistance phenotypes were observed with the highest frequency of resistance exhibited to ampicillin (n=10; 2.35%). The isolates were predominantly pansusceptible (n=409; 96.23%); however, seven isolates were multidrug resistant (MDR; i.e., resistant to three or more antimicrobials). Extended spectrum β-lactamase (ESBL) coding genes (bla(TEM) and bla(PSE)) were detected in the ampicillin-resistant isolates, whereas a single MDR isolate tested positive for class 1 integron (1 kb). The majority of the isolates (n=422; 99.3%) carried the invA, mgtC, stn, sopB, sopE1, and sefA virulence genes. However, 37 (8.7%) and 46 (10.82%) S. Enteritidis isolates tested negative for the plasmid encoded genes spvC and rck, respectively. Pulsed-field gel electrophoresis (PFGE) typing of 118 S. Enteritidis isolates by restriction enzymes XbaI and BlnI resulted in seven clusters, each with a discriminatory index (DI) of 0.715 and 0.785, respectively. The combination of XbaI-BlnI patterns generated a dendrogram with 14 clusters and a higher DI of 0.914. The PFGE profile of 80 isolates matched 100% with the S. Enteritidis strain that has been cited for the recent outbreak in the United States due to consumption of contaminated eggs. In conclusion, we identified a genotypic similar S. Enteritidis population in our study based on antimicrobial susceptibility, virulence gene, and PFGE fingerprint profiles.     

Commensal pseudomonas species isolated from wastewater and freshwater milieus in the eastern cape province, South Africa, as reservoir of antibiotic resistant determinants

Pseudomonas species are opportunistic pathogens with implications in a wide range of diseases including cystic fibrosis and sickle cell anaemia. Because of their status as multidrug resistant (MDR) and extremely drug resistant (XDR) bacteria Pseudomonas species represent a threat to public health. Prevalence, antibiogram and associated antibiotic resistant genes of Pseudomonas species isolated from freshwater and mixed liquor environments in the Eastern Cape Province of South Africa were assessed. Polymerase chain reaction (PCR) based technique was used to identify the isolates and screen for antibiotic resistant genes. The result shows occurrence of Pseudomonas spp. in freshwater and mixed liquor as follows: 71.42% and 37.5% (P. putida), 14.28% and 31.25% (P. flourescens), 7.14% and 6.25% (P. aeruginosa) and 7.14% and 25% for other Pseudomonas species respectively. Disk diffusion antibiogram of the Pseudomonas isolates from the two locations showed 100% resistance to penicillin, oxacillin, clindamycin, rifampicin and 100% susceptibility to ciprofloxacin and gentamicin with varied percentage resistances to cephalothin, nalidixic acid, tetracycline, and ampicillin. The bla(TEM) antibiotic resistant gene was detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% P. aeruginosa and 40% in other Pseudomonas species. Similarly, Integrons conserved segment were detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% of P. aeruginosa and 40% of other Pseudomonas species. The presence of bla(TEM) gene and integrons conserved segment in some of the isolates is worrisome and suggest Pseudomonas species as important reservoirs of multidrug resistance genes in the Eastern Cape Province environment.     

产超广谱β-内酰胺酶肺炎克雷伯菌β-内酰胺酶与Ⅰ类整合酶基因研究

目的了解产超广谱β-内酰胺酶(ESBLs)肺炎克雷伯菌中β-内酰胺酶和Ⅰ类整合酶(intⅠ1)基因存在状况。方法对35株肺炎克雷伯菌,采用聚合酶链反应(PCR)检测TEM、SHV、OKP、CTX-M-1群、CTX-M-2群、CTX-M-9群、GES、PER、VEB、OXA-10、ACT-1、LEN、DHAi、ntⅠ1基因。结果35株肺炎克雷伯菌中检出β-内酰胺酶基因22株,阳性率62.9%;intⅠ1阳性21株,阳性率60.0%。结论产ESBLs肺炎克雷伯菌β-内酰胺酶基因和intⅠ1基因携带率高。